1. Field
In general, the present invention relates to hard disk drives (HDDs). Specifically, the present invention relates to a method and apparatus for reducing coupled hard disk drive vibrations.
2. Related Art
Vibration-related problems are increasingly prominent in high-performance computer systems, such as servers, mainframes, and supercomputers. These vibration-related problems may be caused by several factors. First, cooling fans have become larger, more numerous, and more powerful to compensate for the increased heat generated by the machines' hardware components. In addition, cheaper and more lightweight materials currently used in chassis and support structures are less effective at dampening vibrations than heavier and more expensive materials. Finally, newer generations of internal hard disk drives (HDDs) are more sensitive to vibration-induced degradation.
Specifically, HDDs have increased in both storage density and performance in accordance with Moore's Law. At these increased densities, a write head of an HDD may be required to hit a track that is less than 20 nanometers in width. In addition, the write head may be separated from a corresponding platter by a distance of several nanometers. Finally, the platter may be spinning at speeds of up to 15,000 revolutions per minute (rpm). These factors have caused the latest generation of HDDs to be more sensitive to vibrations. Consequently, vibration-related problems may cause the HDDs within a computer system to experience reductions in read and write throughput. Moreover, the increased internal latencies caused by the degraded throughput may cause software applications to hang, crash, and/or reboot.
To compensate for internally excited vibrations from components within the computer system and externally excited vibrations propagated from adjacent systems, designers often apply damping materials, such as rubber grommets, foam composites, and/or elastomeric pads to areas within and/or around the computer system. These damping materials may be placed to mechanically isolate individual HDDs from vibration-generating components within the computer system and from vibrations produced by adjacent systems. However, these damping materials may further limit available space inside densely packed computing systems, impede cooling airflow, and degrade with age. Hence, alternative methods for reducing vibrations may preserve performance and throughput while avoiding problems associated with the use of damping materials.